Titanium(IV) chloride and the amine-promoted Baylis-Hillman reaction

[GRAPHICS] In the Baylis-Hillman reaction, we found that, when the reactions of arylal dehydes with methyl vinyl ketone were carried out at <-20 degrees C using a catalytic amount of amine as a Lewis base in the presence of titanium(IV) chloride, the chlorinated compounds 1 could be obtained as the major produc t in very high yields for various arylaldehydes. In addition, acrylonitrile could undergo the same reaction to give the corresponding chlorinated prod uct in moderate yield.